This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

ADS8638: ADS8638SRGET

Part Number: ADS8638

Hello All,

I need to use the ADC8638 for 8 ch voltage conversion, it has a good sampling rate and a good resolution, but something came in mind. I see in its datasheet that HVDD and HVSS could be up to plus/minus 15 V, but recommended are plus/minus 10V and that the analog input signal range depend on these supplies. My question is whether it is ok to use plus/minus 15 V which I already have available on my board? I do not have much space left and the conversion to plus/minus 10V would require some.


Thank you!


  • Hello,

    Yes you can set HVDD and HVSS to +15V, and -15V volts respectively. This will cover the widest input range the device can be programmed to of +/-10V

    Regards, Cynthia
  • Thank you! But the max input range is not dictated by HVDD and HVSS? Which would mean that I could achieve plus minus 15 V as input range?
    Besides, my worries were not to damage the converter by putting the max allowable supplies.
    What can you tell me here?

    Regards!

    Matei
  • The input range of the device is software selectable, and the options available are: ±10V, ±5V, ±2.5V, 0V to 5V, or 0V to 10V.

    You will not be able to achieve a +/-15V input.  This is all assuming an internal reference.

    If you use an external reference at the max allowable voltage of 3V, you can increase the input range to +/-12V, but this still would not get as wide as +/-15V.

    The HVDD and the HVSS does in fact affect that input as well. In the image below for the ADS8638 datasheet, the analog input are connected to protection diodes pulled to HVDD and HVSS. This means to make sure the diodes are not turn on during normal operation, that the supplies must be above the expect max/min input voltage signals.

    Regards

    Cynthia